dialyzer

The Dialyzer, a DIscrepancy AnalYZer for ERlang programs

The Dialyzer is a static analysis tool that identifies software
discrepancies such as definite type errors, code which has become
dead or unreachable due to some programming error, unnecessary
tests, etc. in single Erlang modules or entire (sets of)
applications. Dialyzer starts its analysis from either
debug-compiled BEAM bytecode or from Erlang source code. The file
and line number of a discrepancy is reported along with an
indication of what the discrepancy is about. Dialyzer bases its
analysis on the concept of success typings which allows for sound
warnings (no false positives).

Use Dialyzer from the command line to detect defects in the
specified files or directories containing .erl or
.beam files, depending on the type of the
analysis.

-r dirs

Same as the previous but the specified directories are searched
recursively for subdirectories containing .erl or
.beam files in them, depending on the type of
analysis.

--apps applications

Option typically used when building or modifying a plt as in:

dialyzer --build_plt --apps erts kernel stdlib mnesia ...

to conveniently refer to library applications corresponding to the
Erlang/OTP installation. However, the option is general and can also
be used during analysis in order to refer to Erlang/OTP applications.
In addition, file or directory names can also be included, as in:

dialyzer --apps inets ssl ./ebin ../other_lib/ebin/my_module.beam

-o outfile (or
--output outfile)

When using Dialyzer from the command line, send the analysis
results to the specified outfile rather than to stdout.

--raw

When using Dialyzer from the command line, output the raw analysis
results (Erlang terms) instead of the formatted result. The raw format
is easier to post-process (for instance, to filter warnings or to
output HTML pages).

--src

Override the default, which is to analyze BEAM files, and
analyze starting from Erlang source code instead.

-Dname (or -Dname=value)

When analyzing from source, pass the define to Dialyzer. (**)

-I include_dir

When analyzing from source, pass the include_dir
to Dialyzer. (**)

-pa dir

Include dir in the path for Erlang (useful when
analyzing files that have '-include_lib()'
directives).

--output_plt file

Store the plt at the specified file after building it.

--plt plt

Use the specified plt as the initial plt (if the plt was built
during setup the files will be checked for consistency).

--plts plt*

Merge the specified plts to create the initial plt -- requires
that the plts are disjoint (i.e., do not have any module
appearing in more than one plt).
The plts are created in the usual way:

A family of options which selectively turn on/off warnings
(for help on the names of warnings use
dialyzer -Whelp).

--shell

Do not disable the Erlang shell while running the GUI.

--version (or -v)

Print the Dialyzer version and some more information and
exit.

--help (or -h)

Print this message and exit.

--quiet (or -q)

Make Dialyzer a bit more quiet.

--verbose

Make Dialyzer a bit more verbose.

--build_plt

The analysis starts from an empty plt and creates a new one from
the files specified with -c and
-r. Only works for beam files. Use
--plt or --output_plt to
override the default plt location.

--add_to_plt

The plt is extended to also include the files specified with
-c and -r. Use
--plt to specify which plt to start from,
and --output_plt to specify where to put the plt.
Note that the analysis might include files from the plt if they depend
on the new files. This option only works with beam files.

--remove_from_plt

The information from the files specified with
-c and -r is removed
from the plt. Note that this may cause a re-analysis of the remaining
dependent files.

--check_plt

Check the plt for consistency and rebuild it if it is not
up-to-date.

--no_check_plt

Skip the plt check when running Dialyzer. Useful when working with
installed plts that never change.

--plt_info

Make Dialyzer print information about the plt and then quit. The
plt can be specified with --plt(s).

--get_warnings

Make Dialyzer emit warnings even when manipulating the plt.
Warnings are only emitted for files that are actually analyzed.

--dump_callgraph file

Dump the call graph into the specified file whose format is
determined by the file name extension. Supported extensions are: raw,
dot, and ps. If something else is used as file name extension, default
format '.raw' will be used.

--no_native (or -nn)

Bypass the native code compilation of some key files that Dialyzer
heuristically performs when dialyzing many files; this avoids the
compilation time but it may result in (much) longer analysis
time.

--fullpath

Display the full path names of files for which warnings are emitted.

--gui

Use the gs-based GUI.

--wx

Use the wx-based GUI.

Note!

* denotes that multiple occurrences of these options are possible.

** options -D and -I work both from command-line and in the Dialyzer GUI;
the syntax of defines and includes is the same as that used by erlc.

Warning options:

-Wno_return

Suppress warnings for functions that will never return a
value.

-Wno_unused

Suppress warnings for unused functions.

-Wno_improper_lists

Suppress warnings for construction of improper lists.

-Wno_tuple_as_fun

Suppress warnings for using tuples instead of funs.

-Wno_fun_app

Suppress warnings for fun applications that will fail.

-Wno_match

Suppress warnings for patterns that are unused or cannot
match.

-Wno_opaque

Suppress warnings for violations of opaqueness of data types.

-Wunmatched_returns***

Include warnings for function calls which ignore a structured return
value or do not match against one of many possible return
value(s).

-Werror_handling***

Include warnings for functions that only return by means of an
exception.

-Wrace_conditions***

Include warnings for possible race conditions.

-Wbehaviours***

Include warnings about behaviour callbacks which drift from the
published recommended interfaces.

-Wunderspecs***

Warn about underspecified functions
(the -spec is strictly more allowing than the success typing).

The following options are also available but their use is not
recommended: (they are mostly for Dialyzer developers and internal
debugging)

-Woverspecs***

Warn about overspecified functions
(the -spec is strictly less allowing than the success typing).

-Wspecdiffs***

Warn when the -spec is different than the success typing.

Note!

*** Identifies options that turn on warnings rather than
turning them off.

Using the Dialyzer from Erlang

You can also use Dialyzer directly from Erlang. Both the GUI and the
command line versions are available. The options are similar to the ones
given from the command line, so please refer to the sections above for
a description of these.